PAR and the related reflector lamps have found widespread usage in a variety of outdoor residential and commercial applications particularly for lighting residential driveways and yards, entrance ways to buildings, and other similar areas where the wide spread of light output of PAR and reflector lamps provides the necessary safety as well as the convenience features desired for these types of applications. To insure that the safety and convenience features of PAR lamps are enjoyed at all times rather than just when the homeowner or business owner remembers to turn on the lamp, it has become common practice to provide a photosensor arrangement for automatically turning the lamp on when ambient light conditions fall below a certain level. Typical photosensor arrangements for use with PAR lamps come in the form of a separate adaptor base that screws into the socket of a conventional outdoor light fixture with the
lamp then being installed into an equivalent socket on the adaptor. Examples of such adaptor type photosensor devices can be found in U.S. Pat. Nos. 3,056,035; 3,496,422; 3,621,269; and 4,023,035. The problem with this approach to providing a photosensitive actuation of a lighting product particularly a PAR type of lamp is that the adaptor takes up a significant amount of space between the fixture socket and then what becomes the extended outward edge of the lighting product. Because of such size constraints, the use of an adaptor approach is often limited in terms of the number and variety of lighting fixtures in which it can be used. Additionally, for a PAR lamp wherein the light output is directed through the top surface of the lamp and not through the sides as a typical incandescent lamp, it is also a problem in that the fixture typically is made of metal or some other opaque material. As such, with the photosensor of an adaptor configuration disposed substantially below the point at which the ambient light can be accurately sensed, inaccurate readings can be experienced with the sensor detecting the lack of light within the light fixture as an indication that it must now turn on. Accordingly, it would be advantageous if a photosensor arrangement could be provided that would be particularly useful in conjunction with a PAR lamp and the type of fixture in which such a PAR lamp is utilized.
One approach to solving this problem has been to incorporate the photosensor as well as the circuitry associated therewith that monitors the output of the photosensor and turns the lamp on, into the base of the lamp itself and to avoid the use of an adaptor altogether. An example of such a configuration can be found in U.S. Pat. No. 4,988,921. Although such a configuration moves the photosensor up to a point just below the bottom portion of the lamp envelope, it should be noted that such photosensor is still substantially down the length of the lamp such that placement of the combination photosensor/lamp configuration in a fixture designed for use of a PAR lamp results in substantial blockage of the photosensor by the fixture housing. Additionally, the lamp of the '921 reference is in the form of an A-line lamp, not a reflector configuration. As such, though the photosensor is near to the area where light is emitted, the A-line lamp configuration still does not lend itself to use in the types of fixtures typically used for illuminating larger areas around homes and commercial establishments, particularly those applications where a PAR lamp is best suited. Accordingly, it would be advantageous to provide a photosensor and circuit arrangement integral with a PAR lamp which could best be utilized in fixtures generally configured for applications involving illumination of larger areas with the wider beam spread pattern of a PAR lamp.